Tag control for runtime glossmarks

ABSTRACT

The present invention relates to the manipulation of differential gloss as may be inherent in halftoned images by utilization of tags. By selectively applying halftones with anisotropic structure characteristics, which are significantly different in orientation while remaining identical in density, as directed by tag settings, a gloss image may be superimposed within an image without the need for special toners or paper. Conventional copier systems will not typically be able to copy such a superimposed gloss image.

RELATED CASES

[0001] Cross reference is made to the following related applicationsincorporated by reference herein: Attorney Docket Number D/A1744entitled “Application of Glossmarks for Graphics Enhancement”, toinventors Shen-ge Wang, Beilei Xu, and Chu-heng Liu; Attorney DocketNumber D/A1749 entitled “Halftone Image Gloss Control For Glossmarks”,to inventors Shen-ge Wang, Beilei Xu, and Chu-heng Liu.

BACKGROUND

[0002] The present invention relates generally the gloss inherent in thehardcopy of image data be it pictorial or text. More particularly, thisinvention relates to halftoned image data and the control ofdifferential gloss utilizing tags when that halftone image data isprocessed for printing into hardcopy.

[0003] It is desirable to have a way to protect against the copying of adocument. Most desirably in a manner that part of the content can bereadily observed by a human reader but not by a copier scanner. Oneapproach is where an image is printed using clear toner or ink, creatinga difference in reflected light and diffused light that can be discernedby a human reader by holding the paper at an angle, but can not bedetected by a copier scanner which is restricted to reading at rightangles to the page.

[0004] There has been a need for a printer that can print a page thatcan be read but not copied. One method, described in U.S. Pat. Nos.4,210,346 and 5,695,220, is to use a particular white toner and aparticular white paper that are designed to have different diffusedlight characteristics at different angles. Of course, this systemrequires special, matched paper and toner.

[0005] In U.S. Pat. No. 6,108,512 to Hanna, the invention describeddiscloses a system for producing non-copyable prints. In a xerographicprinter, text is printed using clear toner. Thus, the only opticaldifference between toner and non-toner portions of the page is in thereflectivity. The plastic toner will reflect more light than the paper.A human reader can now read the image by holding the page at such anangle that the eye will intercept the reflected light from the toner,producing a contrast between the lighter appearing toner and the darkerappearing paper. However, a copier scanner is always set up to avoidreflected light, by supplying light at an oblique angle and reading at aright angle. In this case, the diffused light is approximately equal forboth toned and untoned surfaces, the scanner will detect no differenceand the copier will not be able to copy the original.

[0006] Another approach taken to provide a document for which copycontrol is provided includes digital watermarking. As an example in U.S.Pat. No. 5,734,752 to Knox, there is disclosed a method for generatingwatermarks in a digitally reproducible document which are substantiallyinvisible when viewed including the steps of: (1) producing a firststochastic screen pattern suitable for reproducing a gray image on adocument; (2) deriving at least one stochastic screen description thatis related to said first pattern; (3) producing a document containingthe first stochastic screen; (4) producing a second document containingone or more of the stochastic screens in combination, whereby uponplacing the first and second document in superposition relationship toallow viewing of both documents together, correlation between the firststochastic pattern on each document occurs everywhere within thedocuments where the first screen is used, and correlation does not occurwhere the area where the derived stochastic screens occur and the imageplaced therein using the derived stochastic screens becomes visible.

[0007] All of the above are herein incorporated by reference in theirentirety for their teaching.

[0008] Therefore, as discussed above, there exists a need for anarrangement and methodology which will control gloss and allowmanipulation for glossmarks without requiring special toners/inks orpaper/substrates, nor require the superimposition of additional printsto allow viewing. Included in this need is the desirability ofgenerating an image which may not be readily copied yet is readilydiscernable as such to the unaided observer. Furthermore, there is aneed for an arrangement to control application of glossmarks within asystem at runtime. Thus, it would be desirable to solve this and otherdeficiencies and disadvantages as discussed above with an improvedmethodology for the manipulation of inherent gloss.

[0009] The present invention relates to a method for the manipulation ofthe differential gloss as may be inherent in a halftone image comprisingthe steps of selecting a first halftone having a first anisotropicstructure orientation, and then selecting a second halftone having asecond anisotropic structure orientation different from the firsthalftone. The first halftone being applied to at least one portion ofthe halftone image, and the second halftone being applied to theremaining portions of the halftone image.

[0010] In particular, the present invention relates to a method for themanipulation of the perceived gloss in a halftone image comprising thesteps of selecting a first halftone having an anisotropic structureorientation, selecting a second halftone having a structure differentfrom that of the first halftone, applying the first halftone to at leastsome portion of the halftone image, and applying the second halftone tothe remaining portion of the halftone image.

[0011] The present invention also relates to a method for themanipulation of the perceived gloss in a halftone image comprising thesteps of selecting a first halftone having a first anisotropic structureorientation, selecting a second halftone having a second anisotropicstructure orientation different from that of the first halftone, thenselecting a third halftone having a structure different from both thefirst halftone and the second halftone. The steps which follow entailapplying the first halftone to at least some portion of the halftoneimage, applying the second halftone to another portion of the halftoneimage, and applying the third halftone to the remaining portion of thehalftone image.

[0012] Further, the present invention relates to a halftone imagecomprising a first halftone having an anisotropic structure orientationand at least one additional halftone type having a structure differentfrom the first halftone. The first halftone is applied to a portion ofthe halftone image and the at least one additional halftone type isapplied to the remainder of the image.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows how the human eye can detect a large differencebetween the glossy portions of the page but a scanner detector can not.

[0014]FIG. 2 depicts a differential gloss found in simple line-screenhalftones.

[0015]FIG. 3 shows two 3×6 halftone patterns suitable in anisotropicstructure to produce discernable gloss differential for practicing thepresent invention.

[0016]FIG. 4 is a density sweep of the two halftone patterns of FIG. 3.

[0017]FIG. 5 depicts a patchwork alternating of the two halftonepatterns of FIG. 3 so as to achieve a glossmark.

[0018]FIG. 6 shows one embodiment for achieving the image directedalternation of the halftone patterns for gloss marks as depicted in FIG.5, utilizing the halftone patterns of FIG. 3.

[0019]FIG. 7 schematically depicts the input and output of CMYK datathrough a Digital Halftone Unit.

[0020]FIG. 8 shows a digital tag byte as provided with a glossmarktoggle bit.

DESCRIPTION

[0021] By proper utilization of the perceived differential glossinherent between various anisotropic halftone dot structures, thedesired manipulation of perceived gloss and the generation of glossmarksvia that differential gloss may be achieved without the need for specialpaper or special toners or inks. Internal system identificationparticularly for utilization by a Digital Halftone Unit (DHU) may beachieved by application of data tagging.

[0022]FIG. 1 shows how the human eye 1 can read gloss upon the page anda scanner cannot. Three glossy areas 14 are shown. One ray of light 10from the light source 2 hits the paper at a point where there is nogloss toner 14, and the reflected light 13 is diffused so that there isonly a small amount of light in all directions, including the directiontoward the human eye 1. Another ray of light 11 of equal intensitytouches the paper at a point where there is gloss toner 14. Here, thereis a large amount of reflected light 12 in the indicated direction. Ifthe human eye 1 is positioned as shown, a large difference betweenglossy and non-glossy toner areas is readily observable by the human eye1. However, the scanner 3 reads incident light at right angles to thepaper. In this case, there is only a small amount of diffused lightcoming from both the glossy and non-glossy dots, and the scanner can notdetect a difference. This is one manner for creating a gloss image whichcannot be scanned by conventional copiers and scanners.

[0023] Heretofore, there has been little appreciation for the fact thatthe inherent reflective and diffusive characteristics of halftones maybe manipulated to be directive of incident light as about an azimuth byuse of a halftone structure which is anisotropic in nature. A mirror isequally reflective regardless of the azimuth of the light sourcerelative to the plane of the mirror. Similarly, an ordinary blank paperis equally reflective and diffusive regardless of the azimuth of thelight source. However, printed matter can and will often displaydiffering reflective and diffusive characteristics depending upon theazimuth of origin for a light source relative to the structuralorientation of the halftone. Such reflective characteristics whenmaximized are exhibited in a halftone with a structure which isanisotropic in nature. In other words the indicatrix used to express thelight scattered or reflected from a halftone dot will maximally varydepending upon the halftone dot's azimuth orientation to the lightsource when that halftone has an anisotropic structure. FIG. 2 providesan example of what is meant by anisotropic structure.

[0024] In FIG. 2, a simple line-screen halftone of anisotropic nature ispresented in two orientations relative to impinging incident light 200,a parallel orientation 210 and a perpendicular orientation 220. Bothhalftone dot orientations are selected to be similar in density so thatthe diffuse light and incident light at orthogonal angles to the paperare equal. In this way, the light which is available to scanner 3 or tothe human eye from straight on is the same. However, the specularreflected light 12 is considerably greater for the anisotropic parallelorientation 210. If as printed, a mass of the 210 parallel orientationhalftones are butted directly adjacent to a mass of 220 perpendicularorientation halftones there will be a difference in reflected lightbetween them, which when viewed from an angle will be perceived as ashift in gloss differential or a glossmark. The perceptibility of thisgloss differential will be maximized when the halftone anisotropicorientations are 90 degrees apart as shown here in FIG. 2.

[0025]FIG. 3 shows example halftone cells suitable for a skilledpractitioner to employ in an embodiment employing the teachings of thepresent invention. They are but one useful example as will be evident tothose skilled in the art. Each halftone cell is comprised as a three bysix pixel array. The turn on/off sequence is numerically indicated. Notethe diagonal orientation of the pixel numbering. The type-A sub-cell 310and type-B sub-cell 320 both have a 45 degree orientation, one to theright and the other to the left. This orientation can be clearly seen inthe density sweeps 410 and 420 of FIG. 4. To maximize the perceptibilityof the gloss differential, the orientations of sub-cells type-A andtype-B are arranged 90 degrees apart one from the other.

[0026]FIG. 5 depicts a glossmark image 500 achievable using halftonecells as described above. Screen-A 510 uses one halftone cell type andscreen-B 520 uses the other. The circle 501 is provided as a visual aidacross the image screens 500, 510 and 520. The desired gloss mark hereis for a sphere 502 to be perceived in the midst of image 500. Screen-A510 provides the field of right diagonal oriented anisotropic halftonesand screen 520 provides the spherical area of left diagonal orientedanisotropic halftone cells. In this manner, a selection of the twoscreen types are patch-worked together to create the glossmark image500.

[0027] An another approach for the assembly of a gloss mark image isdiagramed in FIG. 6. Here, the primary image 600 is received as inputdata to the digital front-end (DFE) 610 as is normal. However, a desiredglossmarking image 620 is also received as input data to the DFE 610 aswell. The processed image as sent to the image output terminal (IOT) 630is gray-scaled, the halftone density being driven by the primary image600 data as is normal. However, the halftone type selection is driven bythe intended glossmarking image data 620 as input to multiplexer switch640. The intended glossmarking image data 620 will serve to direct aportion of the primary image 600 to use a first anisotropic structuredhalftone while directing an alternative halftone to be used for theremainder of primary image 600. As will be understood by those skilledin the art, the intended glossmarking image data 620 may be flattenedinto simple zero and one pixel data representations if needed in the DFE610. This pattern of zero and ones are then used to toggle themultiplexer 640 to one halftone anisotropic structure orientation typeor the other. Multiplexer 640 therefore toggles between either screen 1type halftone 650 or screen 2 halftone type 660 as dictated by thedesired glossmark data 620 to produce the composite result of rasterinput processed (RIP) image data as passed to the IOT 630. In this way,a superimposition of a pattern 620 is imbedded into the primary image600 which can only be perceived as a gloss differential glossmark.

[0028]FIG. 7 shows one possible alternative arrangement for tracking,communicating, and applying the combination of primary image data 600and desired glossmarking image data 620 as utilized in this example asinput to Digital Halftone Unit 700 (DHU). In this scenario, ascontrasted with the embodiment described above, a tag bit has beenpreviously set to one or zero for each pixel location of image data 600in response to the glossmark data 620. This tag bit may have been set bya software application or by a DFE or any number of other places andsituations which will be most apparent to those skilled in the art.Depicted in FIG. 8 as one possible example, a glossmark toggle tag bit800 is encompassed in an 8-bit tag byte 801. The other bits in tag byte801 may comprise a color enhancement bit, or a sharpening (for text)bit, etc. as defined by the system. The tag byte 801 is passed alongwith 8-bit deep CMYK data as input to the DHU 700 via input port 720.However, the omega/tag channel, over which the tag byte 801 is passed,is directed to latch 710. The glossmark toggle tag bit 800 is latchedand used to direct screen selector 730. As directed by the glossmarktoggle tag bit 800, screen selector 730 pulls from storage either screen1 type halftone 650 or screen 2 halftone type 660 and supplies that toDHU 700 for halftoning. This allows DHU 700 to provide 1-bit deep CMYKraster data as output 740.

[0029] In closing, by alternating between two halftone types, carefullyselected by tag assignment where each halftone type has identicalmatching density characteristics while displaying distinctly differentanisotropic structure orientations will enable the super imposition of aglossmark image without the need for special toners or paper. Thismanipulation of gloss differentials will, of course, be best utilizedwith toner/ink and substrate systems which themselves best displayinherent gloss characteristics. Examples of such systems compriseelectrostaticgraphic and quality ink-jet systems. While wax basedsystems typically have less inherent gloss they may well prove amendableto techniques which increase their inherent gloss. In just such ascenario, the teachings herein are anticipated to apply such wax basedsystems as well. It will be appreciated by those skilled in the art thatthese teachings will apply to both monochromatic, black and white, aswell as color images and upon plain paper, glossy paper ortransparencies. Those skilled in the art will also understand that thismanipulation of inherent anisotropic gloss differential will be weakwhere either there is a solid black area (solid toner/ink) or a whiteand therefore toner-less/ink-less area. That is because these areas willnot best exhibit the anisotropic structures of the selected halftones.

[0030] While the embodiments disclosed herein are preferred, it will beappreciated from this teaching that various alternative modifications,variations or improvements therein may be made by those skilled in theart. For example, it will be understood by those skilled in the art thatthe teachings provided herein may be applicable to many types ofhalftone cell types and arrangements including selecting more than twodifferent halftone structures, as well being applicable to many types oftoner/ink and substrate types. All such variants are intended to beencompassed by the following claims:

1. A method for the manipulation of the differential gloss in a halftoneimage comprising the steps of: receiving primary image data; receivingdesired glossmarking image data; and, tagging of at least some portionof the primary image data, as directed by the desired glossmarking imagewith a first tag setting.
 2. The method of claim 1 wherein the halftoneimage is intended for an inkjet printer.
 3. The method of claim 1wherein the halftone image is intended for an electrostaticgraphicprinter.
 4. The method of claim 1 wherein the halftone image is intendedfor printing upon paper.
 5. The method of claim 1 wherein the halftoneimage is intended for printing upon a transparency.
 6. A method for themanipulation of the differential gloss in a halftone image comprisingthe steps of: receiving primary image data; receiving desiredglossmarking image data; tagging of at least some portion of the primaryimage data, as directed by the desired glossmarking image with at leastone tag setting; applying a first halftone having an anisotropicstructure orientation to the primary image data as per the tag setting;and, applying a second halftone different from that of the firsthalftone to the remaining portion of the primary image data.
 7. Themethod of claim 6 wherein the second halftone is a stochastic type. 8.The method of claim 6 wherein the second halftone is a cluster dot type.9. The method of claim 6 wherein the halftone image is intended for anelectrostaticgraphic printer.
 10. The method of claim 6 wherein thehalftone image is intended for an ink jet printer.
 11. A method for themanipulation of the differential gloss in a halftone image comprisingthe steps of: receiving primary image data; receiving desiredglossmarking image data; tagging of at least some portion of the primaryimage data, as directed by the desired glossmarking image with at leasta first and a second tag setting; applying a first halftone having afirst anisotropic structure orientation to the primary image data as perthe first tag setting; and, applying a second halftone having a secondanisotropic structure orientation different from that of the firsthalftone to the primary image data as per the second tag setting. 12.The method of claim 11 wherein the first anisotropic structureorientation and the second anisotropic structure orientation are 90degrees apart.
 13. The method of claim 11 wherein the first anisotropicstructure orientation and the second anisotropic structure orientationare less than 90 degrees apart.
 14. The method of claim 12 wherein thefirst anisotropic structure has a 45 degree orientation to the right andthe second anisotropic structure has a 45 degree orientation to theleft.
 15. The method of claim 11 wherein the halftone image is intendedfor an electrostaticgraphic printer.
 16. The method of claim 11 whereinthe halftone image is intended for an ink jet printer.
 17. The method ofclaim 11 wherein the halftone image is intended for printing upon paper.18. The method of claim 11 wherein the halftone image is intended forprinting upon a transparency.